Jason Pfeiffer, Alleged Michael Jackson Lover, Sues Dr. Arnold Klein For Harming Singer, Himself

Jason Pfeiffer, the former assistant to Michael Jackson's dermatologist, Dr. Arnold Klein, is suing him for putting MJ's life in danger, according to a new lawsuit.

Pfeiffer, who has made headlines for alleging he had a gay affair with Michael Jackson, says that "Throughout 2009, Michael was a frequent patient of Klein."

The lawsuit says, "Several times, Klein told Pfeiffer to help Michael down to the car because Michael was too drugged up and disoriented to stand on his own."

Jason Pfeiffer says he voiced his concern for Michael's "safety" because he and Klein's nurses "were worried Michael was being 'overmedicated' by Klein."

Pfeiffer says Klein simply told him to "keep his mouth shut."

Moreover, Pfeiffer claims Klein tried to sneak MJ prescription muscle relaxants in 2009 by writing a prescription in Pfeiffer's name. Pfeiffer claims he refused.

He goes on to make various other allegations against Klein:

Sometime around October 2008, Pfeiffer says Klein was contacted by Michael Jackson, who told the dermatologist he "needed 'to get out of a court appearance' and needed a doctor's note." Klein allegedly obliged.

According to the suit, Klein told MJ he would take care of it and issued a note saying he was suffering from a staph infection, based on a bogus test.

For what it's worth, Klein's treatment of MJ has been questioned in the past.

The last days of Michael Jackson have put Dr. Conrad Murray under a microscope, but in the months leading up to June 2009, Klein had been sedating the star.

Klein has always denied allegations of wrongdoing and maintained that he treated Michael in accordance with the highest medical standards.

Pfeiffer's allegations get weirder still. MUCH weirder.

He claims he was wrongfully terminated by Klein, and in the lawsuit, filed Wednesday in Klein's ongoing bankruptcy case, Pfeiffer alleges Klein forced him to help "round up" gay sex partners, including prostitutes and homeless people.

Pfeiffer also claims he would have to help "prepare" Klein for his sexual encounters. Specifically, "Klein required that Pfeiffer wash Klein's groin."

Pfeiffer, who says his gay affair with MJ began after they met via Klein, says he suffered severe emotional issue as a result of Klein's treatment .

He is suing for unspecified damages.

A lawyer for Klein tells TMZ in response to this: "Dr. Klein is one of the most esteemed and respected dermatologists in his profession in the country."

"This counterclaim is totally unfounded, and frankly it's garbage. The claims in Dr. Klein's lawsuit are very serious, and we're taking them all the way."